/* Layout — Sidebar, Header, Main Content */
:root {
    --sidebar-width: 260px;
    --header-height: 56px;
    --sidebar-bg: #1e293b;
    --sidebar-hover: #334155;
    --sidebar-active: #3b82f6;
    --primary: #2563eb;
    --success: #16a34a;
    --warning: #d97706;
    --danger: #dc2626;
    --critical: #991b1b;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: #f1f5f9;
    min-height: 100vh;
}

.app-wrapper {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.app-sidebar {
    width: var(--sidebar-width);
    background: var(--sidebar-bg);
    color: #e2e8f0;
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    overflow-y: auto;
    z-index: 1040;
    transition: transform 0.3s ease;
}

.sidebar-brand {
    padding: 1rem 1.25rem;
    border-bottom: 1px solid #334155;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.sidebar-brand .brand-icon {
    width: 36px;
    height: 36px;
    background: var(--primary);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.85rem;
}

.sidebar-brand .brand-text {
    font-size: 0.9rem;
    font-weight: 600;
    line-height: 1.2;
}

.sidebar-nav {
    padding: 0.75rem 0;
}

.nav-section-title {
    padding: 0.5rem 1.25rem;
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: #64748b;
    font-weight: 600;
}

.sidebar-nav .nav-link {
    color: #cbd5e1;
    padding: 0.5rem 1.25rem;
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    border-left: 3px solid transparent;
    transition: all 0.15s;
}

.sidebar-nav .nav-link:hover {
    background: var(--sidebar-hover);
    color: #fff;
}

.sidebar-nav .nav-link.active {
    background: rgba(59, 130, 246, 0.15);
    color: #fff;
    border-left-color: var(--sidebar-active);
}

.sidebar-nav .nav-link i {
    width: 18px;
    text-align: center;
    opacity: 0.8;
}

.nav-submenu {
    padding-left: 0.5rem;
}

.nav-submenu .nav-link {
    padding-left: 2.5rem;
    font-size: 0.8125rem;
}

/* Header */
.app-header {
    position: fixed;
    top: 0;
    left: var(--sidebar-width);
    right: 0;
    height: var(--header-height);
    background: #fff;
    border-bottom: 1px solid #e2e8f0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1.5rem;
    z-index: 1030;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.header-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #1e293b;
    margin: 0;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    font-size: 0.875rem;
    color: #64748b;
}

.header-date, .header-user {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.sidebar-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.25rem;
    color: #475569;
    cursor: pointer;
}

/* Main content */
.app-main {
    margin-left: var(--sidebar-width);
    margin-top: var(--header-height);
    padding: 1.5rem;
    flex: 1;
    min-height: calc(100vh - var(--header-height));
}

.page-header {
    margin-bottom: 1.25rem;
}

.page-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #0f172a;
    margin-bottom: 0.25rem;
}

.breadcrumb-bar {
    font-size: 0.8125rem;
    color: #64748b;
}

.breadcrumb-bar a {
    color: var(--primary);
    text-decoration: none;
}

.breadcrumb-bar a:hover {
    text-decoration: underline;
}